1. Field of the Invention
The present invention generally relates to medical devices, methods and systems for selectively contracting tissues, particularly for the treatment of urinary incontinence.
Urinary incontinence arises in both men and women with varying degrees of severity, and from different causes. In men, the condition most frequently occurs as a result of prostatectomies which result in mechanical damage to the urethral sphincter. In women, the condition typically arises after pregnancy when musculoskeletal damage has occurred as a result of inelastic stretching of the structures which support the genitourinary tract. Specifically, pregnancy can result in inelastic stretching of the pelvic floor, the external sphincter, and the tissue structures which support the bladder and bladder neck region. In each of these cases, urinary leakage typically occurs when a patient's abdominal pressure increases as a result of stress, e.g., coughing, sneezing, laughing, exercise, or the like.
Treatment of urinary incontinence can take a variety of forms. Most simply, the patient can wear absorptive devices or clothing, which is often sufficient for minor leakage events. Alternatively or additionally, patients may undertake exercises intended to strengthen the muscles in the pelvic region, or may attempt a behavior modification intended to reduce the incidence of urinary leakage.
In cases where such non-interventional approaches are inadequate or unacceptable, the patient may undergo surgery to correct the problem. A wide variety of procedures have been developed to correct urinary incontinence in women. Several of these procedures are specifically intended to support the bladder neck region. For example, sutures, straps or other artificial structures are often looped around the bladder neck and affixed to the pelvis, the endopelvic fascia, the ligaments which support the bladder, or the like. Other procedures involve surgical injections of bulking agents, inflatable balloons, or other elements to mechanically support the bladder neck.
An alternative surgical procedure which is performed to enhance support of the bladder is the Kelly plication. This involves midline plication of the fascia, particularly for repair of central defects. In this transvaginal procedure, the endopelvic fascia from either side of the urethra is approximated and attached together using silk or linen suture. A similar procedure, anterior colporrhaphy, involves exposing the pubocervical fascia and reapproximating or plicating portions of this tissue from either side of the midline with absorbable sutures. While the Kelly plication and its variations are now often used for repair of cystocele, this procedure was originally described for the treatment of incontinence.
Each of these known procedures has associated shortcomings. Surgical operations which involve midline plications or direct suturing of the tissues of the urethra or bladder neck region require great skill and care to achieve the proper level of artificial support. In other words, it is necessary to occlude or support the tissue sufficiently to inhibit urinary leakage, but not so much that intentional voiding is made difficult or impossible. Balloons and other bulking agents which have been inserted can migrate or be absorbed by the body. The presence of such foreign body inserts can also be a source of urinary tract infections.
Alternative devices, systems, and methods for treatment of urinary incontinence have recently been proposed in U.S. patent application Ser. No. 08/910,370, filed Aug. 13, 1997, and assigned to the assignee of the present invention. This reference, which is incorporated herein by reference, describes techniques for treating urinary incontinence by applying sufficient energy to tissue structures that comprise or support the patient's urethra so as to cause partial shrinkage of the tissue, and thereby inhibit incontinence. Hence, these techniques generally involve selectively contracting a patient's own pelvic support tissues, often applying gentle heating of the collagenated endopelvic structures to cause them to contract without imposing significant injury on the surrounding tissues. U.S. patent application Ser. No. 08/910,775, filed Aug. 13, 1997, describes related non-invasive devices, methods and systems for shrinking of tissues and is also incorporated herein by reference.
While these new methods for treatment of incontinence by selectively contracting tissues represent a significant advancement in the art, still further improvements would be desirable for treating urinary incontinence in men and women. In particular, it would be desirable to provide devices and therapies to reliably and repeatably contract tissues so as to effect the intended physiological change. It would be best if these improved techniques and structures could provide reliable results independent of the normal variations in the skill and experience of the surgeon. It would further be desirable if these improved techniques could be performed using minimally invasive techniques so as to reduce patient trauma, while retaining and/or enhancing the overall efficacy of the procedure.
2. Description of the Background Art
The following U.S. patents and other publications may be relevant to the present invention: U.S. Pat. Nos. 4,453,536; 4,679,561; 4,765,331; 4,802,479; 5,190,517; 5,281,217; 5,293,869; 5,314,465; 5,314,466; 5,370,675; 5,423,811; 5,458,596; 5,496,312; 5,514,130; 5,536,267; 5,569,242; 5,588,960; 5,697,882; 5,697,909; and P.C.T. Published Application No. WO 97/20510.